Generally, a mobile handset is a communication device capable of performing a voice transmission and reception with a remote party, and is generally simply carried by a user. Information communication technology has progressed and the mobile handset can also transmit/receive text messages, access the Internet, and receive TV signals. The mobile handset can also function as a camera capable of taking, transmitting, and receiving still photographs and motion videos. Additional uses for the mobile handset are being developed continuously.
The mobile handset generally has one of several form types—a bar type mobile handset, a flip type mobile handset, a folder type mobile handset, or a slider type mobile handset.
A battery supplies power to the mobile handset and the battery may be detached from the handset for charging in a separate charger, or when being replaced by a fully charged battery. A memory card for external memory also may be mounted in the handset body.
FIG. 1 is a disassembled perspective view showing a mobile handset in accordance with the conventional art, and FIG. 2 is a partial sectional view showing the mobile handset. As shown, the mobile handset comprises a body 100 having a certain shape, and a battery 200 detachably coupled to one side of the body 100 for supplying power.
The body 100 comprises a body casing 111 having a certain shape, a printed circuit board (PCB) 130 mounted in the body casing 111, and a key pad (not shown) mounted in the body casing 111. The body casing 111 comprises a front case 110 and a rear case 120 coupled to the front case 110. A compartment 121 for mounting the battery 200 is formed at the rear case 120.
Connection terminals 140 are formed on an inner side of the battery compartment 121, and the connection terminals 140 are connected to other components. A memory card slot 122 and a SIM card slot 123 are respectively formed on a surface of the battery compartment 121 for mounting a memory card 300 and a SIM card 310 respectively. The memory card 300 and the SIM card 310 are connected to chips inside the handset body 100 by signal lines in order to exchange data and signals.
The battery 200 comprises a battery body 210 formed to have a certain thickness and area, connection terminals 220, and a stopping groove 230. A battery latch for securing or releasing the battery 200 within the battery compartment 121 is provided on one side of the handset body 100.
The battery latch comprises a guide groove 124 having a certain length, a locking member 150 formed with a certain shape, and a spring 160 positioned in the handset body 100 for biasing the locking member 150 in the direction of the battery compartment 121. The guide groove 124 is penetratingly formed at one side of the handset body 100 and positioned at an edge of the battery compartment 121. The locking member 150 is coupled to the handset body 150 by spring 160 and is slideable within the guide groove 124.
The locking member 150 comprises a step portion 151 for insertion into the stopping groove 230 of the battery, a contact portion 152 for sliding within the guide groove 124, and a spring support portion 153. Spring 160 is disposed between locking member 150 and the handset body 100, and couples the locking member 150 to the handset body.
The mobile handset is used when the battery 200 is mounted within the battery compartment 121 and secured with the locking member 150. When the battery 200 is completely discharged, the locking member 150 is released thereby allowing the battery 200 to separate from the handset body 100. The battery 200 then may be charged in a separate charger, or a replacement battery may be inserted into the battery compartment 121.
The battery 200 is mounted to the handset body 100 as follows: the locking member 150 is slideably moved into the handset body 100 in a direction away from the battery compartment 121 thereby compressing spring 160, the battery 200 is inserted into the battery compartment 121, and the locking member 150 is released. The spring 160 biases the locking member 150 to the original position causing the step portion 151 to be inserted into the locking groove 230 thereby securing the battery 200 into the battery compartment 121.
The battery 200 is removed from the handset body 100 as follows: the locking member 150 is slideably moved into the handset body 100 in a direction away from the battery compartment 121 thereby compressing spring 160, the step portion 151 retracts from the locking groove 230 thereby releasing the battery 200 from the battery compartment 121. The battery 200 now may be separated from the handset body 100. The memory card 300 and SIM card 310 may be removed from or inserted into their respective slots 122 and 123 after the battery 200 is separated from the handset body 100.
However, in the conventional mobile handset, when the battery 200 is separated from the handset body 100, and the memory card 300 and the SIM card 310 are inserted into handset body 100, static electricity may be generated causing a potential difference between the cards and the handset body 100 or between the user and the handset body 100.
Static electricity discharges to components mounted within the handset body 100 through the memory card 300 or the SIM card 310 generating severe errors. To reduce the effect of static electricity and the associated errors, a static preventing circuit is provided as shown in FIG. 3. The static preventing circuit is constructed as a static preventing filter 315 connected between signal lines 325 and ground. Signal lines 325 provide signals between the SIM card 310 (or the memory card 300, not shown) to the components of the handset body 100. Ground lines 335 connect the static preventing filter 315 to ground.
However, the conventional static preventing circuit has a limitation in suppressing static electricity. The operational speed of communication lines 325 is dependent upon the capacitance associated of the communication lines 325, and because the static prevention filter 315 adds capacitance, the effective communication speed of lines 325 is reduced. Therefore, operating the communication lines 325 without reducing the communications speed increases the chance of erroneous communications. Data communication speed of line L1 is critical especially considering the enhanced performance and functionality of the mobile handset. Therefore, protecting the mobile handset hardware and software from the static electricity is important.